Giant Hogweed, Heracleum mantegazzianum

Giant hogweed was introduced into Europe and North America from Asia in the early 1900's. It's impressive growth made it a desirable garden plant. However, giant hogweed soon escaped cultivation and established itself in natural areas in several states including Maine.

Along with its impressive growth habit, giant hogweed is also noteworthy because its sap can cause severe skin irritation. When susceptible people come in contact with the sap and the skin is then exposed to sunlight, painful blisters develop.

The Department is in the process of trying to locate populations of this plant and could use your help. Several plants including cow parsnip, angelica and poison hemlock, look similar to giant hogweed. When trying to identify giant hogweed plants look for the following characteristics:

Very tall plants, 8-14 feet in height
Stems that are 2-4 inches in diameter with rigid hairs, purple blotches and are hollow
Leaves that are unevenly lobed and up to 5 feet long
Flowers clusters up to 2 feet across occurring from mid June to late July
Dead stems that remain upright throughout the winter

If you must handle this plant be careful not to come into contact with sap from broken stems. You should be well covered, wearing gloves, long sleeves and long pants.

If you see any of these plants in Maine, please contact us at Ann.Gibbs@maine.gov

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Giant Hogweed, Heracleum mantegazzianum